﻿package com.sz.common.crypt;

import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
/**
 * @author malaoba
 *
 */
public class AESCrypt {

 /** 
  * 加密 
  * @param content 需要加密的内容 
  * @param keyWord  加密密钥 
  * @return byte[]  加密后的字节数组
  */  
 public static byte[] encrypt(String content, String keyWord) {  
         try {             
                 KeyGenerator kgen = KeyGenerator.getInstance("AES");
                 SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );  
                 secureRandom.setSeed(keyWord.getBytes());  
                 kgen.init(128,secureRandom);  
                 SecretKey secretKey = kgen.generateKey();  
                 byte[] enCodeFormat = secretKey.getEncoded();  
                 SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");  
                 Cipher cipher = Cipher.getInstance("AES");// 创建密码器  
                 byte[] byteContent = content.getBytes("utf-8");  
                 cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化  
                 byte[] result = cipher.doFinal(byteContent);  
                 return result; // 加密  
         } catch (Exception e) {  
                 e.printStackTrace();  
         } 
         return null;  
 }
 /**
  * @param content 需要加密的内容
  * @param password 加密密钥
  * @return String  加密后的字符串
  */
 public static String encrypttoStr(String content, String password){
  return parseByte2HexStr(encrypt(content,password));  
 }
 /**解密 
  * @param content  待解密内容 
  * @param keyWord 解密密钥 
  * @return  byte[]
  */  
 public static byte[] decrypt(byte[] content, String keyWord) {
         try {  
                  KeyGenerator kgen = KeyGenerator.getInstance("AES");  
                  SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );  
                 secureRandom.setSeed(keyWord.getBytes());  
                 kgen.init(128,secureRandom);  
                SecretKey secretKey = kgen.generateKey();  
                  byte[] enCodeFormat = secretKey.getEncoded();  
                  SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");              
                  Cipher cipher = Cipher.getInstance("AES");// 创建密码器  
                 cipher.init(Cipher.DECRYPT_MODE, key);// 初始化  
                 byte[] result = cipher.doFinal(content);  
                 return result; // 加密  
         } catch (Exception e) {  
                 e.printStackTrace();  
         } 
         return null;  
 }
 /**
  * @param content 待解密内容(字符串)
  * @param keyWord 解密密钥
  * @return byte[]
  */
 public static byte[] decrypt(String content, String keyWord) {
  return decrypt(parseHexStr2Byte(content),keyWord);  
 }
 
 /**
  * 解密成字符串
  * @param content
  * @param keyWord
  * @return
  */
 public static String decrypttoStr(String content, String keyWord) {
	  return new String(decrypt(parseHexStr2Byte(content),keyWord));  
	 }
 
 /**将二进制转换成16进制 
  * @param buf 
  * @return  String
  */  
 public static String parseByte2HexStr(byte buf[]) {  
         StringBuffer sb = new StringBuffer();  
         for (int i = 0; i < buf.length; i++) {  
                 String hex = Integer.toHexString(buf[i] & 0xFF);  
                 if (hex.length() == 1) {  
                         hex = '0' + hex;  
                 }  
                 sb.append(hex.toUpperCase());  
         }  
         return sb.toString();  
 }
 /**将16进制转换为二进制 
  * @param hexStr 
  * @return  byte[]
  */  
 public static byte[] parseHexStr2Byte(String hexStr) {  
         if (hexStr.length() < 1)  
                 return null;  
         byte[] result = new byte[hexStr.length()/2];  
         for (int i = 0;i< hexStr.length()/2; i++) {  
                 int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);  
                 int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);  
                 result[i] = (byte) (high * 16 + low);  
         }  
         return result;  
 }  


 public static void main(String[] args) {
  String content = "test";  
  String Key = "Freedom and Democracy";  
  
  //加密
  System.out.println("加密前：" + content);
  String encryptResult = encrypttoStr(content, Key);
  System.out.println("加密后：" + encryptResult); 
  //解密  
  byte[] decryptResult = decrypt(encryptResult,Key);  
  System.out.println("解密后：" + new String(decryptResult)); 
 }
}

